If you are running RH9, is your HW also that old? If so, could be hot fault/aging chip somewhere.
Does the re-boot happen at same time each time? Dieing HW isn't usually that repeatable.
Also, RH9 is so old that there's no more support for it, inc security patches.
Can you upgrade to a current version?
The free version is now RH Fedora Core 6, or you can get Centos, which is the RH Enterprise version, but re-badged & free.
Anyway, good luck & let us know how it goes.